No Exception On Dojo Chain Calls

I spend about 1 or 2 days a week on learning and exploring Dojo. I really like this JavaScript based API framework. I found one very nice feature of Dojo. Not only you can call Dojo methods by using Dojo chain calls, and you don't need to worry about if any middle part of the chain returns undefined or not.

For example, I added the following codes to the head's script section:

dojo.addOnLoad(function() {
  console.log("OnLoad ready to add events");
  dojo.query("#testHeadingEvent")
    .style("cursor", "pointer")
    .connect("onclick", function() {
      this.innerHTML="I've been clicked";
      });
  console.log("Onload fires adding event on headEvent");
});

the query() function returns a DOM node by id. If the node is not found, it's still OK. No exception is thrown. I can still see the messages print out on the console(by using FireBug add-on). Isn't that nice?